In the case of refrigerant compressors used for air conditioning and heat pump applications, sound has become an increasingly important criteria for judging user acceptance. Accordingly, there is a demand for improved refrigerant compressors and refrigeration system which are quieter than those presently available, while sacrificing none of the advantages of existing compressors and refrigeration systems.
In this regard, the design and use of compressor unit shells must take into account many factors including the gas flow volumes and flow patterns within the shell and the space limitations of the shell with regard to accommodating various compressor components including the sizes, shapes and arrangement of discharge mufflers, suction plenums, discharge gas shock loops and the like. For example, while improved sound attenuation is usually achieved by increasing the muffler size and the number of baffles or the like contained therein, the adverse increased pressure drop across the muffler leads not only to reduced compressor efficiency, i.e., lowered Btu/Hr/Watts, but also to excessive strain on mechanical parts of the compressor such, e.g., as through irregular or fluttering discharge valve operation. Also, while the sizes of such components may aid in noise reduction, prior designs incorporating such have increased the weight of the unit to such an extent that the added shipping and handling costs as well as the additional expenses of material and manufacture have more than offset the advantages attained in the noise reduction.